The present invention relates to a locking mechanism for a vehicle seat, in particular for an automobile seat.
In a known locking mechanism for a vehicle seat, an upper member of the mechanism is supported on a bearing element, which is supported in a lower member of the mechanism. The bearing element, which is arranged in an assembly space between the upper member and the lower member of the mechanism and constructed as a complicated combination of collars, is used at the same time as a control cam element for moving two locking elements. The locking elements are pushed radially outward, while being guided in a guideway, for engaging the locking mechanism. The combined bearing and control cam element is mounted directly on a transmission bar. After installing the locking mechanism in an automobile seat, this transmission bar extends to the locking mechanism on the other side and to an adjustment device. By rotating the transmission bar, the bearing and control cam element rotates, thereby moving the locking elements.
It is an object of the present invention to improve a locking mechanism of a vehicle seat. According to one aspect of the invention, this object is accomplished by a locking mechanism having a lower member including a guideway with a bearing surface for engaging an upper member so that the upper member is supported by the lower member and the upper and lower members are relatively rotatable about a central axis. The locking mechanism further includes a locking element that is within a channel of the guideway and is driven radially away from the central axis by a control element in response to rotation of the control element, so that the locking element engages both the lower member and the upper member to restrict rotation of the upper member relative to the lower member.
The fact that the guideway forms the bearing for supporting the upper member permits supporting the upper member directly in or on the lower member of the mechanism without a bearing element as an intermediate support. With that, it is no longer necessary to use a bearing and control cam element of a complicated construction, which simplifies production of the locking mechanism and reduces its costs. Additionally, the guideway radially extends further outward than the known bearing and control cam element, so that a support occurs with a longer lever arm, which reduces the bearing forces. Preferably, the guideway is made integral with the lower member of the locking mechanism and supported in the upper member thereof, thereby simplifying production and increasing stability.
For a safe engagement of the locking mechanism, a gear rim that is preferably formed on one member of the mechanism in a boundary surface thereof cooperates with a locking element that is designed and constructed as a toothed segment. Preferably, two locking elements are provided. For a simple manufacture, it is advantageous for the boundary surface that comprises the gear rim to function as the bearing contact surface for the guideway. To effect an as satisfactory support as possible, the guideway preferably lies against the boundary surface over the largest portion of the sector range in the circumferential direction. Recessed sector ranges are left open, for example, for the locking elements or for accommodating springs.
The support of the upper member via the guideway permits using the space in the center of the locking mechanism for receiving the control element. As mentioned above, the control element moves the locking elements. To assist this movement, the control element is preferably spring-loaded. For applying the necessary force, a spring is provided preferably for each locking element. A control disk is preferably mounted to a transmission bar with the control element for moving the locking elements in the direction against the spring load.
In a preferred embodiment, means are provided for equalizing tolerances, so that a safe engagement of the locking mechanism is achieved. When each side of the automobile seat mounts a locking mechanism, and a common actuation occurs via a bar, the tolerance equalization means will, for example, see to it that both locking mechanisms engage, regardless as to whether different tooth positions in the locking mechanisms occur as a result of a play that is intentionally provided within a locking mechanism, or as a result of manufacturing tolerances. For example, the tolerance equalization means may also compensate for tolerances within a locking mechanism. The different tolerance equalization means may be provided individually or in any desired combinations. Preferably, a control element moves the locking elements. In this instance, the control element is moved by a bar, which transmits the movement of the control element from one side of the vehicle seat to the other side thereof. This effects a synchronous actuation of all existing locking elements. To make up for torsions of the bar, it is preferred to provide a play between the bar and the control element. For a simpler manufacture, it is advantageous to provide the play between a separately made transmission element, that is shorter than the bar and arranged on the bar, and the control element.
As a further tolerance equalization means, the control element can be designed and constructed as a cam plate, with a contoured control section for each existing locking element. In this instance, each contoured control section extends outward in a slightly spiral form with a constantly increasing radius. As a result, a partially engaged locking element is safely held until all the other locking elements are also engaged. Control cams accomplish a better transmission of force to the locking elements, which cooperate with the respective contoured control section.
Preferably, a control disk is provided for cooperating with each locking element. The control disk lies against the locking element laterally with respect to the direction of movement thereof, and controls the movement of the locking element, for example via projections and slots, in particular during disengagement. Preferably, the control disk is biased in the direction toward the locking element, namely in the axial direction in the case of a radially movable locking element. This ensures that the control disk remains in contact with the locking element, and thus, the projections and slots remain engaged for controlling the movement. The bias is realized, preferably by one or more resilient tongues, which are bent outward from the control disk, and which are simultaneously operative as a tolerance equalization means.
In a further, preferred embodiment, the locking mechanism comprises a means which restricts an effective operation of the locking element to certain angular positions between the upper and the lower member of the locking mechanism. This permits using the locking mechanism in automobile seats whose seat back should be adapted for free pivotal movement after disengagement and/or for movement to a reclined position, without having to actuate or hold the disengagement device constantly during the pivotal movement. This makes it easy to reach and to abandon likewise the foremost or rearmost angular position of the seat back. In the reclined position, it is further ensured that the seat back is supported, and that the load is not transmitted via a locking mechanism with an unfavorable lever arm, which is inadvertently engaged barely above the reclined position.
Preferably, the locking element cooperates for purposes of engaging with one of the members of the locking mechanism. Outside of certain angular positions, the means keeps the locking element away from this member of the mechanism. This may occur, for example, by a retaining or return means, a guide plate control, individual stops, cams, or by a stop track, which extends over several connected angular positions. In the case of a radially operative locking element, the stop track cooperates preferably with an axially projecting detent of the locking element in order not to be directly in the flow of the engagement force, and to protect the effective engagement surface of the locking element, for example a gear tooth system. In this instance, the stop track can include radially different, far outside located sections, which serve as stops for the axially projecting detent.
Preferably, the stop track is arranged on the upper member of the locking mechanism, since in this instance the stop track rotates over the different angular positions along with the upper member, and can therefore be designed and constructed in a simpler manner. As a function of the number of locking elements, the stop track is accordingly shaped in rotational symmetry.
To have available individually adapted stop tracks, which can be easily exchanged or left off, if desired, the stop track can advantageously be provided on a separately constructed part, which is nonrotatably arranged on the upper member of the locking mechanism. In the case of an easy-to-make antirotation device, the separately constructed part comprises projections and/or receptacles, which cooperate with corresponding receptacles or projections of the upper member of the locking mechanism. To be able to continue the use of previously used parts, without increasing the overall depth and without providing a stop track, if need be, it will be of advantage, when the separately constructed part is, for example, a ring, which is seated in a recess of the upper member of the locking mechanism.
In a further, preferred embodiment, the locking mechanism comprises an element that can be coupled with either the lower member or the upper member of the mechanism. This permits a free pivotal movement of a mounted seat back with a memory function, i.e., after the free pivotal movement, the adjusted position is again reached. As a result of directly supporting the lower and upper members of the locking mechanism on the guideway without an intermediate bearing, it is no longer necessary to use a bearing and control cam element of a complicated construction, which simplifies production of the locking mechanism and reduces its cost. Since the guideway extends radially further outward than the known bearing and control cam element, a support occurs with a longer lever arm, which reduces the bearing forces.
The coupling with the upper and lower members of the mechanism may occur by arms, for example, spring arms. Preferably, these arms can be disconnected from the respective member by a common shift plate. To actuate the shift plate, it is preferred to provide a rotatable actuation sleeve, which is nonrotatably connected to the shift plate arranged inside the locking mechanism and to a lever arranged outside of the locking mechanism. For a compensation of axial tolerances, it is possible to provide third spring arms.
Preferably, the locking element comprises a detent, and a guide plate with a step is provided, over which the detent moves during a free pivotal movement of the locking mechanism, so that the locking element does not engage. To receive the detent, while the locking mechanism engages, the guide plate may comprise a recess. Preferably, this guide plate forms at the same time the engageable element that can be coupled with the aforesaid arms.
An automobile seat of the present invention comprises at least one, preferably two of the locking mechanisms according to the invention, which are interconnected via the transmission bar.